Local Storage¶

Introduction¶

The Local Storage method group exposes the per-Product, per-device key-value store a Product uses to remember values between sessions, such as user preferences, drafts, and cached values. The Product SDK wraps this group as a KvStore in the @parity/product-sdk-local-storage package.

Two properties matter for how this group is shaped:

• Per-Product namespacing: The Host prepends every key with a prefix derived from the Product's .dot domain. A Product cannot accidentally read or write another Product's keys; the boundary is at the Host, not in the Product's code.
• Host-dependent backend: Inside Polkadot Desktop, reads and writes go to the Host's on-device storage. Inside Polkadot Web, the Host backs them with browser-managed storage. The SDK abstracts the difference; the Product's code is identical either way.

Conceptual Contract¶

The group exposes the standard key-value surface plus a few helpers:

• get(key), set(key, value), and remove(key): Read, write, and delete a string-valued key.
• getJSON(key) and setJSON(key, value): Read and write JSON-serializable values, with the Host handling encoding.
• Prefixed-namespace creation: A Product can carve out further sub-namespaces inside its own per-Product space, useful when multiple Product features share the store and want to avoid collisions.

Reads return null for absent keys; deletes are idempotent (no error on missing keys).

Where to Go Next¶